What is the median for class a and class b?

You need to write all the numbers out in order from least to greatest. 

You have 4, 4, 4, 4, 4, 5, 5, 5, 6, 6, 12, 13, 13, 13, 13, 14

Now cross off one number at a time from both edges
4, 4, 4, 4, 5, 5, 5, 6, 6, 12, 13, 13, 13, 13
4, 4, 4, 5, 5, 5, 6, 6, 12, 13, 13, 13
...and so on until you get to the middle. In this case, the middle is 5, 6, so you take the number between that which would be 5.5, or 5

3cm and 6 and 9 cm that a possibility of that question